Relative Muscle Cross-sectional Area Research Articles

Comparison of lumbar muscle morphology in patients with chronic nonspecific low back pain with and without clinical lumbar segmental instability.

Evaluation of spinal muscle morphology may be critical because of its impact on segmental stability and control of the lumbar spine in the subset of patients with clinical lumbar segmental instability (LSI). The purpose of this study was to compare lumbar muscle morphology in CNLBP patients with clinical LSI, CNLBP patients without clinical LSI. This case-control study included 30 patients with CNLBP (15 with clinical LSI and 15 without clinical LSI) and 15 subjects without LBP. Axial magnetic resonance images from the L2 to S1 lumbar levels were used to evaluate the morphology of the lumbar muscles. A significant increase in the muscle-to-fat infiltration index and a significant decrease in the relative muscle cross-sectional area (rmCSA) of the multifidus muscle at the L3-L4 to L5-S1 levels were observed in both CNLBP groups compared to the control group (p<0.05). The mean erector spinae mean rmCSA was significantly greater in the clinical LSI group compared to the control group (SMD = 0.853, 95% CI = 0.105 to -1.6, P = 0.044) and also compared to the CNLBP without clinical LSI (SMD = 0.894, 95% CI = -1.645 to -0.144, P = 0.030) at the L4-L5 level. The atrophic changes of the multifidus muscle, in CNLBP patients with or without clinical LSI was observed. However, hypertrophic changes of the erector spinae muscle at the L4-L5 lumbar level were observed only in the clinical LSI group. Psaos major did not show significant atrophic or hypertrophic changes.

Role of Menopausal Transition and Physical Activity in Loss of Lean and Muscle Mass: A Follow-Up Study in Middle-Aged Finnish Women.

In midlife, women experience hormonal changes due to menopausal transition. A decrease especially in estradiol has been hypothesized to cause loss of muscle mass. This study investigated the effect of menopausal transition on changes in lean and muscle mass, from the total body to the muscle fiber level, among 47–55-year-old women. Data were used from the Estrogenic Regulation of Muscle Apoptosis (ERMA) study, where 234 women were followed from perimenopause to early postmenopause. Hormone levels (estradiol and follicle stimulating hormone), total and regional body composition (dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) scans), physical activity level (self-reported and accelerometer-measured) and muscle fiber properties (muscle biopsy) were assessed at baseline and at early postmenopause. Significant decreases were seen in lean body mass (LBM), lean body mass index (LBMI), appendicular lean mass (ALM), appendicular lean mass index (ALMI), leg lean mass and thigh muscle cross-sectional area (CSA). Menopausal status was a significant predictor for all tested muscle mass variables, while physical activity was an additional significant contributor for LBM, ALM, ALMI, leg lean mass and relative muscle CSA. Menopausal transition was associated with loss of muscle mass at multiple anatomical levels, while physical activity was beneficial for the maintenance of skeletal muscle mass.

The scaling of terrestrial striking performance in western ratsnakes (Pantherophis obsoletus).

In many organisms, juveniles have performance capabilities that partly offset their disadvantageous sizes. Using high-speed video recordings and imaging software, we measured the scaling of head morphology, axial morphology, and defensive strike performance of Pantherophis obsoletus across their ontogeny to understand how size and morphology affect performance. Head measurements were negatively allometric whereas the cross-sectional area (CSA) of epaxial muscles displayed positive allometry. The greater relative muscle CSA of larger ratsnakes allows them to produce higher forces relative to their mass, and those forces act on a relatively smaller head mass when it is thrust forward during striking. Maximum strike accelerations of 70-273.8 ms-2 and velocities of 1.08-3.39 ms-1 scaled positively with body mass but differed from the geometric predictions. Velocity scaled with mass0.15 and acceleration scaled with mass0.17 . Larger snakes struck from greater distances (range = 4.1-26 cm), but all snakes covered the strike distances with similarly short durations (84 ± 3 ms). The negatively allometric head size, isometry of anterior mass, and positively allometric muscle CSA enable larger P. obsoletus to strike with higher velocities and accelerations than smaller individuals. Our results contrast with the scaling of strike performance in an arboreal viper, whose strike distance and velocity were independent of body mass. When strike distance is modulated, all other performance capacities are affected because of the interdependence of acceleration, velocity, duration, and distance.

Potential Role of Paraspinal Musculature in the Maintenance of Spinopelvic Alignment in Patients With Adult Spinal Deformities.

A retrospective observational study. To (1) compare skeletal muscle mass index (SMI) and the composition of paraspinal muscles between patients with lumbar spinal stenosis (LSS) and adult spinal deformity (ASD) who underwent spinal surgery, (2) determine whether paraspinal muscles influence low back pain in ASD, and (3) ascertain which radiographic spinal parameters of ASD are predominantly influenced by paraspinal muscles. Relative muscle cross-sectional area (rmCSA; total CSA minus intramuscular fat CSA) determined using magnetic resonance imaging (MRI) is useful when evaluating not only muscle volume but also muscle quality. Currently, no study has examined paraspinal muscles using rmCSAs to determine which radiographic spinopelvic parameters identified in patients with severe spinal deformities make them candidates for thoracolumbar corrective surgery. Paraspinal muscle rmCSAs were calculated using preoperative T2-weighted MRIs at the L3/4 axial level. Whole-body bone mineral density and lean, soft tissue mass were measured using dual-energy x-ray absorptiometry. SMI was calculated as appendicular (upper and lower limbs) lean, soft tissue mass (kg/m). Correlations between low back pain according to the Roland-Morris Disability Questionnaire, Oswestry Disability Index, spinopelvic parameters, and rmCSA were evaluated for 110 consecutive patients with ASD and 50 consecutive patients with LSS who underwent spinal surgery. There was no significant difference in the total SMI and morbidity rate of sarcopenia between patients with ASD and LSS. A significant negative correlation between Oswestry Disability Index and the rmCSA of the multifidus muscles and the rmCSA of the erector muscles were observed. There was a significant positive correlation between pelvic tilt/sacral slope and multifidus/erector muscles. Paraspinal muscles evaluated with MRI were more significantly associated with the pathology of ASD compared with appendicular skeletal muscle evaluations with dual-energy x-ray absorptiometry. The present study indicates that multifidus and erector muscles significantly influenced the maintenance of the pelvic alignment. Level III.

Ambulatory function in motor incomplete spinal cord injury: a magnetic resonance imaging study of spinal cord edema and lower extremity muscle morphometry.

Study DesignThis research utilized a cross-sectional design.ObjectivesSpinal cord edema length has been measured with T2-weighted sagittal MRI to predict motor recovery following spinal cord injury. The purpose of our study was to establish the correlational value of axial spinal cord edema using T2-weighted MRI. We hypothesized a direct relationship between the size of damage on axial MRI and walking ability, motor function, and distal muscle changes seen in motor incomplete spinal cord injury (iSCI).SettingUniversity based laboratory in Chicago, IL USA.MethodsFourteen participants with iSCI took part in the study. Spinal cord axial damage ratios were assessed using axial T2-weighted MRI. Walking ability was investigated using the 6-minute walk test and daily stride counts. Maximum plantarflexion torque was quantified using isometric dynomometry. Muscle fat infiltration (MFI) and relative muscle cross sectional area (rmCSA) were quantified using fat/water separation magnetic resonance imaging.ResultsDamage ratios were negatively correlated with distance walked in 6 minutes, average daily strides, and maximum plantarflexion torque, and a negative linear trend was found between damage ratios and lower leg rmCSA. While damage ratios were not significantly correlated with MFI, we found significantly higher MFI in the wheelchair user participant group compared to community walkers.ConclusionsDamage ratios may be useful in prognosis of motor recovery in spinal cord injury. The results warrant a large multi-site research study to investigate the value of high-resolution axial T2-weighted imaging to predict walking recovery following motor incomplete spinal cord injury.

Trunk Muscle Characteristics of the Multifidi, Erector Spinae, Psoas, and Quadratus Lumborum in Older Adults With and Without Chronic Low Back Pain.

Study Design Cross-sectional study. Objective To determine whether there are differences in trunk muscle characteristics between older adults with and without chronic low back pain (LBP), while controlling for age, sex, and body mass index. Background Muscle support for the trunk is provided by the multifidi, erector spinae, psoas, and quadratus lumborum. Trunk muscle characteristics may be altered with aging and/or chronic LBP. To date, most trunk muscle research has been conducted among younger adults. Given age-related muscle changes, such as reduced size and increased intramuscular fat, studies are needed in older adults, including those comparing older adults with and without LBP. Methods One hundred two older adults with (n = 53) and without (n = 49) chronic LBP were included. Cross-sectional area (CSA) measurements were taken by tracing inside the fascial borders on magnetic resonance images. Pixel intensity summaries were obtained to compute muscle-to-fat indices and relative muscle CSA, that is, CSA void of fat. Right/left averages for levels L2 through L5 were determined. Mixed-design analyses of covariance were used to test for differences between groups, based on LBP presence and sex, across levels (P≤.05). Results Older adults with LBP had a greater average multifidus muscle-to-fat index (0.51 versus 0.49) and smaller average erector spinae relative muscle CSA (8.56 cm2 versus 9.26 cm2) when compared to control participants without LBP. No interactions between LBP status and average muscle characteristics were found for the psoas or quadratus lumborum (P>.05). Conclusion Up to 54% of older adult trunk muscle CSA may be fat. Women have smaller muscles and greater intramuscular fat (at lower spinal levels) than men. J Orthop Sports Phys Ther 2017;47(3):173-179. Epub 3 Feb 2017. doi:10.2519/jospt.2017.7002.

Multifidi Muscle Characteristics and Physical Function Among Older Adults With and Without Chronic Low Back Pain

ObjectiveTo determine whether multifidi size, intramuscular fat, or both, are associated with self-reported and performance-based physical function in older adults with and without chronic low back pain (LBP). DesignCase-control study. SettingIndividuals participated in a standardized evaluation in a clinical laboratory and underwent magnetic resonance imaging (MRI) of the lumbar spine at a nearby facility. ParticipantsA volunteer sample of community-dwelling older adults (N=106), aged 60 to 85 years, with (n=57) and without (n=49) chronic LBP were included in this secondary data analysis. InterventionAverage right-left L5 multifidi relative (ie, total) cross-sectional area (CSA), muscle-fat infiltration index (MFI) (ie, a measure of intramuscular fat), and relative muscle CSA (rmCSA) (ie, total CSA minus intramuscular fat CSA) were determined from MRIs. Linear regression modeling was performed with physical function measures as the dependent variables. Age, sex, and body mass index were entered as covariates. The main effects of L5 multifidi MFI and rmCSA, as well as their interaction with group assignment, were compared as independent variables. Main Outcome MeasuresMedical Outcomes Study 36-Item Short-Form Health Survey physical functioning subscale, timed Up and Go, gait speed, and fast stair descent performance. ResultsInteraction terms between L5 multifidi MFI and group assignment were found to be significant contributors to the variance explained in all physical function measures (P≤.012). Neither the main effect nor the interaction with group assignment for L5 multifidi rmCSA significantly contributed to the variance explained in any of the physical function measures (P>.012). ConclusionsAmong older adults with chronic LBP of at least moderate intensity, L5 multifidi muscle composition, but not size, may help to explain physical function.

Trunk Muscle Size and Composition Assessment in Older Adults with Chronic Low Back Pain: An Intra-Examiner and Inter-Examiner Reliability Study

To evaluate intra- and inter-examiner reliability for the assessment of relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area, i.e., total cross-sectional area minus intramuscular fat, from T1-weighted magnetic resonance images obtained in older adults with chronic low back pain. Reliability study. n = 13 (69.3 ± 8.2 years old) After lumbar magnetic resonance imaging, two examiners produced relative cross-sectional area measurements of multifidi, erector spinae, psoas, and quadratus lumborum by tracing regions of interest just inside fascial borders. Pixel-intensity summaries were used to determine muscle-to-fat infiltration indices; relative muscle cross-sectional area was calculated. Intraclass correlation coefficients were used to estimate intra- and inter-examiner reliability; standard error of measurement was calculated. Intra-examiner intraclass correlation coefficient point estimates for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area were excellent for multifidi and erector spinae across levels L2-L5 (ICC = 0.77-0.99). At L3, intra-examiner reliability was excellent for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area for both psoas and quadratus lumborum (ICC = 0.81-0.99). Inter-examiner intraclass correlation coefficients ranged from poor to excellent for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area. Assessment of relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area in older adults with chronic low back pain can be reliably determined by one examiner from T1-weighted images. Such assessments provide valuable information, as muscle-to-fat infiltration indices and relative muscle cross-sectional area indicate that a substantial amount of relative cross-sectional area may be magnetic resonance-visible intramuscular fat in older adults with chronic low back pain.

Morphological changes in the cervical muscles of women with chronic whiplash can be modified with exercise-A pilot study.

In this preliminary study we determined whether MRI markers of cervical muscle degeneration [elevated muscle fatty infiltration (MFI), cross-sectional area (CSA), and reduced relative muscle CSA (rmCSA)] could be modified with exercise in patients with chronic whiplash. Five women with chronic whiplash undertook 10 weeks of neck exercise. MRI measures of the cervical multifidus (posterior) and longus capitus/colli (anterior) muscles, neck muscle strength, and self-reported neck disability were recorded at baseline and at completion of the exercise program. Overall significant increases in CSA and rmCSA were observed for both muscles, but significant reductions in MFI were only evident in the cervical multifidus muscle. These changes coincided with increased muscle strength and reduced neck disability. MRI markers of muscle morphology in individuals with chronic whiplash appear to be modifiable with exercise.

Pilot study for reconstruction of soft tissues: muscle cross-sectional area of the forearm estimated from cortical bone for a Neolithic sample.

On a basis of a method for muscle cross-sectional area estimation from cortical bone area that was previously developed (Slizewski et al. Anat Rec 2013; 296:1695-1707), we reconstructed muscle cross-sectional area at 65% of radius length for a sample of Neolithic human remains from the Linear Pottery Culture (ca. 5,700-4,900 years BC). Muscle cross-sectional area estimations for the Neolithic sample were compared to in vivo measurements from a recent human sample. Results demonstrate that the Neolithic individuals had larger muscle cross-sectional area relative to radius length than the contemporary humans and that their forearms were more muscular and robust. We also found significant differences in relative muscle cross-sectional area between Neolithic and recent children that indicate different levels of physical stress and isometric activities. Our results fit into the framework of studies previously published about the sample and the Linear Pottery Culture. Therefore, the new approach was successfully applied to an archaeological sample for the first time here. Results of our pilot study indicate that muscle cross-sectional area estimation could in the future supplement other anthropological methods currently in use for the analysis of postcranial remains.

Differential Changes in Muscle Composition Exist in Traumatic and Nontraumatic Neck Pain

A population based cross-sectional study. To clarify relative constituents of viable muscle in 2-dimensional cross-sectional area (CSA) measures of ventral and dorsal cervical muscles in patients with chronic whiplash-associated disorders (WAD), idiopathic neck pain, and healthy controls. Previous data using T1-weighted magnetic resonance image demonstrated large amounts of neck muscle fat infiltration and increased neck muscle CSA in patients with chronic WAD but not in idiopathic neck pain or healthy controls. Magnetic resonance images were obtained for 14 cervical muscle regions in 136 females, including 79 with chronic whiplash, 23 with chronic idiopathic neck pain, and 34 healthy controls. Without fat removed, relative CSA of 7 of 14 muscle regions in the participants with chronic WAD was larger, 3 of 14 smaller and 4 of 14 similar to healthy individuals. When T1-weighted signal representing the lipid content of these muscles was removed, 8 of 14 relative muscle CSA in patients with whiplash were similar, 5 of 14 were smaller and only 1 of 14 was larger than those observed in healthy controls. Removal of fat from the relative CSA measurement did not alter findings between participants with idiopathic neck pain and healthy controls. These findings clarify that previous reports of increased relative CSA in patients with chronic whiplash represent cervical muscle pseudohypertrophy. Relative muscle CSA measures reveal atrophy in several muscles in both patients with WAD and idiopathic neck pain, which supports inclusion of muscle conditioning in the total management of these patients. 3.

Metabolic capacity, fibre type area and capillarization of rat plantaris muscle. Effects of age, overload and training and relationship with fatigue resistance

1. 1. The influences of age (5, 13 and 25-month-old rats), overload as obtained by denervation of synergists, and training on the metabolic capacity, relative muscle cross-sectional area occupied by each fibre type, capillarization and fatigue resistance of the rat m. plantaris were investigated. 2. 2. Creatine kinase, phosphorylase and citrate synthase activities were lower in muscles of 25 than in those of 13-month-old rats ( P < 0.001). 3. 3. Overload resulted in an increased relative area of type I and II a fibres at all ages ( P = 0.001). 4. 4. Capillary density decreased with overload and increasing age ( P < 0.001). 5. 5. Fatigue resistance was higher in muscles of 13 than in those of 5-month-old rats ( P < 0.05), and increased with overload ( P < 0.05) at all ages. 6. 6. Fatigue resistance of the whole muscle was not closely related to its oxidative capacity in contrast to what is generally found for single fibres or motor units.